Date of Award

Spring 5-2026

Document Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Department

Civil & Environmental Engineering

Program/Concentration

Civil and Environmental Engineering

Committee Director

Sandeep Kumar

Committee Member

Mujde Erten-Unal

Committee Member

Alvin Holder

Abstract

This dissertation investigates integrated strategies for resource recovery from waste and biomass streams to support the transition toward a circular bioeconomy. The central problem addressed is the limited efficiency and scalability of current methods for converting biological and geochemical resources into valuable products. To overcome these limitations, the research develops and evaluates innovative processes that couple biochemical, ecological, and mineral recovery systems using experimental and simulation-based approaches.

Microalgal biomass was processed using a rapid, acid-assisted flash hydrolysis process under subcritical conditions to improve the simultaneous recovery of fermentable sugars and lipids. The optimized process achieved nearly complete carbohydrate solubilization with minimal degradation and retained high lipid content, demonstrating a low-energy pathway for integrated biorefinery applications. Complementary studies on benthic polyculture-based Algal Turf Scrubber (ATS) systems established their effectiveness for concurrent nutrient recovery and biomass generation, achieving stable productivity and high nutrient removal rates under variable environmental conditions.

The framework was extended to mineral resource recovery through techno-economic analysis (TEA) of lithium extraction from geothermal brine. A zirconium-doped hydrogenated manganese oxide (Zr-HMZO) ion-sieve direct lithium extraction process achieved over 90% lithium recovery, reduced water use by up to 90%, and shortened residence time by more than 95% compared to solar evaporation. Integration with geothermal heat improved energy efficiency and sustainability.

Overall, the results demonstrate that combining biochemical conversion, ecological treatment, and mineral extraction processes enables high-efficiency resource recovery from diverse waste and biomass streams. These integrated pathways provide scalable, low-carbon solutions that advance the development of resilient circular bioeconomy systems.

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DOI

10.25777/ytmv-gf76

ORCID

0009-0004-3235-9701

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